Turbocharged and supercharged engines may be configured to compress ambient air entering the engine in order to increase power. Because compression of the air may cause an increase in air temperature, a charge air cooler may be utilized to cool the heated air thereby increasing its density and further increasing the potential power of the engine. If the humidity of the ambient air is high, however, condensation (e.g., water droplets) may form on internal surfaces of the charge air cooler that are cooler than the dew point of the compressed air. During transient conditions such as hard vehicle acceleration, these water droplets may be blown out of the charge air cooler and into the combustion chambers of the engine resulting in increased potential for engine misfire, loss of torque and engine speed, and incomplete combustion, for example.
One approach for controlling condensate in a charge air cooler is described in U.S. patent application Ser. No. 2007/0251249. Here, a vibration transducer is activated to vibrate the surfaces of the charge air cooler and break up accumulated condensate into small droplets, in order to detach the condensate from the surfaces of the charge air cooler and sweep it to the engine in small quantities. However, the amount of condensate in the charge air cooler can vary with operating conditions, and activation of the vibration transducer may not be sufficient to dislodge larger quantities of condensate.
The inventors have recognized the issues with the above approach and offer a method to at least partly address them. In one embodiment, a method for an engine comprises cooling intake air through a charge air cooler and adjusting a vibration device of the charge air cooler based on charge air cooler condensation conditions.
In this way, the vibration device may be activated based on condensation conditions within the charge air cooler. For example, if conditions indicate a large (higher) amount of condensate has accumulated within the charge air cooler, the intensity of the vibrations emitted by the device may be increased. Furthermore, by activating the device responsive to condensate formation, the device may remain deactivated during conditions of no (or lower) condensate accumulation, reducing the energy needed to operate the device.
In some examples, the vibration device may be coordinately controlled with a charge air cooler valve arranged in the inlet of the charge air cooler. The charge air cooler valve may selectively modulate intake air flow through the charge air cooler; for example, the intake air may flow through the entirety of the charge air cooler when the charge air cooler valve is open and flow through a subset of the charge air cooler when the valve is closed. By directing intake air through a subset of the charge air cooler, intake air velocity increases, reducing accumulation of condensate on the surfaces of the charge air cooler and/or entraining condensate into the intake air flow. In one example, by combining control of the vibration device with the charge air cooler valve (e.g., by adjusting the vibration device activation and/or intensity based on the valve position, or vice versa), the vibration device may be used to disperse collected condensate during conditions of lower condensate formation, while the charge air cooler valve may be closed to disperse and prevent accumulation of condensate during conditions of higher condensate formation. Furthermore, in other examples, the vibration device may be used to disperse condensate during conditions where the charge air cooler valve is prevented from closing, such as during high load conditions where maximal cooling of the intake air is indicated.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.